Moisture became trapped under a ridge of high pressure which caused dense fog to form.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GJT wrote it up.
Moisture became trapped under a ridge of high pressure which caused dense fog to form.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Junction, CO wrote its last area forecast discussion before the first event at Dec 20, 4:29 AM MST, 24 minutes earlier.
AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE GRAND JUNCTION CO 429 AM MST FRI DEC 20 2013 CORRECTED MISSPELLING .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 415 AM MST FRI DEC 20 2013 A WELL-DEFINED UPPER LOW WAS OVER NRN BAJA EARLY THIS MORNING WHILE THE NORTHERN SECTION OF THE SPLIT TROUGH WAS SHEARING ACROSS THE NORTHERN PLAINS. DEFORMATION/TROUGH/CONVERGENT AXIS WAS ORIENTED SW TO NE ACROSS NE UT/NW CO BETWEEN THESE TWO FEATURES. AN UPPER JET MAX CROSSED SW CO EARLIER IN THE NIGHT AND WAS MOVING INTO THE PLAINS. SURFACE OBS AND WEBCAMS INDICATED SNOW ACROSS MUCH OF NW CO AS WELL AS THE CENTRAL AND SRN MTNS. A VERY NARROW BAND OF HEAVIER SNOW PRODUCED A QUICK 1 TO 2 INCHES OF SNOW FROM RIFLE THROUGH GLENWOOD CANYON TO EAGLE AS IT PROGRESSED EASTWARD... INDICATIVE OF A SLANTWISE CONVECTIVE ELEMENT TO THE PRECIPITATION. THIS BAND STRETCHED BACK TO COLLBRAN/GRAND MESA. DENSE FOG HAS BEEN IN AND OUT OF THE VERNAL AREA PER THE METAR OBSERVATION VARYING BETWEEN 1/4 AND 2 MILES VISIBILITY...SO WILL KEEP THE DENSE FOG ADVISORY INTACT FOR THE EASTERN UINTA BASIN UNTIL MID- MORNING. GENERALLY UNSETTLED WEATHER IS EXPECTED TODAY AS THAT DEFORMATION AXIS SLIDES SOUTHEAST ACROSS THE AREA. EXPECT MAINLY SCATTERED SNOW SHOWERS IN THE VALLEYS WITH SNOW SHOWERS ACROSS THE MOUNTAINS THROUGH MIDDAY...THEN SLOWLY ENDING FROM THE NW OVER THE COURSE OF THE AFTERNOON. MTN SNOW ACCUMULATIONS SHOULD GENERALLY BE 2-6 INCHES...SO NO HIGHLIGHTS AT THIS TIME....THOUGH LOCALLY HIGHER AMOUNTS ARE POSSIBLE. THE BULK OF THE ENERGY ASSOCIATED WITH THE UPPER LOW OVER NRN BAJA SHOULD REMAIN JUST TO OUR SOUTH. THERE WILL BE A BIT OF BREAK TONIGHT BEFORE THE NEXT SHORTWAVE DISTURBANCE DROPS DOWN ACROSS UT ON SATURDAY. SNOW WILL LIKELY RETURN TO THE NRN MTNS BY SAT MORNING AND INTO THE CENTRAL AND SOUTHERN MTNS DURING THE DAY. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 415 AM MST FRI DEC 20 2013 A RATHER MOIST NW FLOW SETS UP SATURDAY NIGHT AS A QUICK MOVING SYSTEM DROPS DOWN FROM THE GREAT BASIN. UNLIKE THE LAST SYSTEM...THE BEST UPPER LEVEL SUPPORT STAYS TO THE WEST AND NORTH AND WEAKENS WITH TIME. BOTH NAM AND GFS BEAR THIS OUT WITH QPF AMTS LOWERING AS PRECIP STARTS SPREADING ACROSS ERN UT AND WRN CO. THE ELKHEADS AND PARK RANGES AND ALSO FLATTOPS ARE FAVORED WITH THIS STORM WITH MAYBE 4 TO 5 INCHES POSSIBLE WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE WITH LOWER AMOUNTS EXPECTED FOR THE CENTRAL MTNS...GRAND MESA AND AREAS SOUTH. BY SUNDAY AFTERNOON...ENERGY WILL HAVE SHIFTED EAST TAKING MOST PRECIP WITH IT THOUGH OROGRAPHICS WILL CONTINUE WITH LGT SNOW SHOWERS CONTINUING UP NORTH. BY MONDAY EVENING...THE ENTIRE CWA LOOKS TO BE PRECIP FREE AS ANOTHER WAVE APPROACHES. 24 HOURS AGO THE MODELS WERE SHOWING SOME DECENT PRECIP FOR THE CWA TUE NIGHT INTO WED...FAVORING THE NORTH AGAIN...BUT LATEST RUNS HAVE REDUCED PRECIP TO ALMOST NIL. EXAMINATION OF THE JET STREAM SHOWS THE SUPPORT FOR THIS SYSTEM WANING AS IT IS USED TO BREAK DOWN THE UPPER LEVEL RIDGE MONDAY AND TUESDAY. WITH LITTLE TO NO ENERGY AVAILABLE TO THE TROUGH...WIDE SCALE ASCENT DROPS LOWERING PRECIP CHANCES. BY WED EVENING...ANY PRECIP THAT MAY FALL WILL END AS NW FLOW CONTINUES AND RIDGING BUILDS INTO THE WEST COAST. AS FAR AS INVERSIONS ARE CONCERNED...DOES NOT LOOK LIKE A REPRIEVE ANY TIME SOON AS MIXING LOOKS TO BE AT A MINIMUM WITH THE STRONGEST UPPER LEVEL WINDS STAYING AWAY FROM THE CWA. AS HAS BEEN COMMON LATELY...WILL UNDERCUT MOS GUIDANCE BY A FEW DEGREES EACH DAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 415 AM MST FRI DEC 20 2013 SMORGASBORD OF WEATHER ONGOING THIS MORNING WITH FOG AT KVEL AND KGJT AND SNOW BEING REPORTED AT MANY OTHER TAF SITES WITH IFR CONDITIONS BEING COMMON. FOR MOST OF THE DAY...EXPECT FLIGHT CONDITIONS TO VARY CONSIDERABLY FROM VFR TO IFR AND BELOW UNDER BANDS OF SNOW SHOWERS THOUGH THESE SHOWERS ARE EXPECTED TO SHIFT MORE TO THE SOUTH AFTER ABOUT 21Z. KVEL WILL REMAIN MVFR DUE TO FOG AND HAZE AND EXPECT NRN AIRPORTS TO BECOME VFR LATER TODAY WITH CHANCES INCREASING FOR FOG TO FORM IN THE VALLEYS OVERNIGHT. MOUNTAIN OBSCURATIONS EXPECTED FOR ALL MOUNTAINS ALONG THE CONTINENTAL DIVIDE. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING UTZ024. && SHORT TERM...JAD LONG TERM...TGR AVIATION...TGR
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
The national radar mosaic for the moment the first event began.
1 dense fog. Local standard time, as filed.
Dense fog occurred across eastern Grand County with visibilities down to a quarter mile or less.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2013Every state in 2013This day in weather historyWarnings in Utah, December 2013
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 515338.